[PATCH] e1000e: do not panic on malformed rx_desc

From: Tong Zhang
Date: Tue Sep 08 2020 - 12:29:22 EST


length may be corrupted in rx_desc and lead to panic, so check the
sanity before passing it to skb_put

[ 103.840572] skbuff: skb_over_panic: text:ffffffff8f432cc1 len:61585 put:61585 head:ffff88805642b800 data:ffff88805642b840 tail:0xf0d1 end:0x6c0 dev:e
th0
[ 103.841283] ------------[ cut here ]------------
[ 103.841515] kernel BUG at net/core/skbuff.c:109!
[ 103.841749] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN PTI
[ 103.842063] CPU: 1 PID: 276 Comm: ping Tainted: G W 5.8.0+ #4
[ 103.842857] RIP: 0010:skb_panic+0xc4/0xc6
[ 103.843022] Code: 89 f0 48 c7 c7 60 f2 3e 90 55 48 8b 74 24 18 4d 89 f9 56 48 8b 54 24 18 4c 89 e6 52 48 8b 44 24 18 4c 89 ea 50 e8 01 c5 2a ff <0f>
0b 4c 8b 64 24 18 e8 c1 b4 48 ff 48 c7 c1 e0 fc 3e 90 44 89 ee
[ 103.843766] RSP: 0018:ffff88806d109c58 EFLAGS: 00010282
[ 103.843976] RAX: 000000000000008c RBX: ffff8880683407c0 RCX: 0000000000000000
[ 103.844262] RDX: 1ffff1100da24c91 RSI: 0000000000000008 RDI: ffffed100da2137e
[ 103.844548] RBP: ffff88806bdcc000 R08: 000000000000008c R09: ffffed100da25cfb
[ 103.844834] R10: ffff88806d12e7d7 R11: ffffed100da25cfa R12: ffffffff903efd20
[ 103.845123] R13: ffffffff8f432cc1 R14: 000000000000f091 R15: ffff88805642b800
[ 103.845410] FS: 00007efcd06852c0(0000) GS:ffff88806d100000(0000) knlGS:0000000000000000
[ 103.845734] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 103.845966] CR2: 00007efccf94f8dc CR3: 0000000064810000 CR4: 00000000000006e0
[ 103.846254] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 103.846539] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 103.846823] Call Trace:
[ 103.846925] <IRQ>
[ 103.847013] ? e1000_clean_rx_irq+0x311/0x630
[ 103.847190] skb_put.cold+0x2b/0x4d
[ 103.847334] e1000_clean_rx_irq+0x311/0x630

Signed-off-by: Tong Zhang <ztong0001@xxxxxxxxx>
---
drivers/net/ethernet/intel/e1000e/netdev.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
index 664e8ccc88d2..f12bd00b2dbf 100644
--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -1047,6 +1047,10 @@ static bool e1000_clean_rx_irq(struct e1000_ring *rx_ring, int *work_done,
}
/* else just continue with the old one */
}
+ /* check length sanity */
+ if (skb->tail + length > skb->end) {
+ length = skb->end - skb->tail;
+ }
/* end copybreak code */
skb_put(skb, length);

--
2.25.1